Locomotive smokebox arrangement



Dec. 24, 1940. w E CQLUNS 2,226,052

LOCOMOTIVE SMOKEBOX ARRANGEMENT Filed April 22,1939

ATTORNEYS Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a locomotive smokebox arrangement. The smokebox arrangement of a locomotive is the extension of the boiler shell ahead of the front flue sheet and is sometimes called the front end arrangement. It comprises the smoke stack, stack extension, exhaust pipe, exhaust nozzle, netting device, and partitions, or diaphragms, or aprons, table plates, draft sheet, deflecting plate when used.

The function of thesmokebox arrangement is to draw air for combustion through the ash pan, grates and fire bed and after a certain portion of the air has served to make combustion possible, to move the products of combustion or gases, and cinders through the fire box over the brick arch and through the tubes and fiues to the smokebox where they are ejected with the exhaust steam from the main cylinders through the stack to the atmosphere. In addition to the function of providing air for combustion the smokebox arrangement must also take care of the sparks. Sparks must be reduced in size and not carry suflicient heat to ignite anything with which they come in contact after being discharged, neither must they be collected or accumulated in the smokebox. This latter requirement makes it necessary that the gases travel at a high velocity through the restricted openings in the smokebox in order that the cinders be thrown with suflicient force against the diaphragm, aprons, smokebox door or netting box to break them into suflioiently small particles to pass through the netting.

A great deal of study, and many devices have been produced, in an attempt to permit sufficient quantity of air being drawn into the fire box to burn the quantity of fuel or coal in a given time, and promote satisfactory combustion conditions, boiler capacity, or rate of evaporation required, or the maximum obtainable at the lowest or least exhaust-pressure which is in turn controlled by the area type and kind of the exhaust nozzle used.

The conventional smokebox arrangement 10- cates the table plate at such a height that the area under it for the passage of the gases or products of combustion ranges from to 110 percent of the area for the gases through the flues and tubes of the boiler. The draft plate used in conjunction with the conventional smokebox arrangement is located at such a height that the area under it ranges from'65% to of the gas area of the fiues and tubes of the boiler. The area. under the table .plate is measured between the bottom edge of the plate and the bottom of the smokebox. The gas area through the tubes and fines is the net area.

The design of the conventional smokebox arwhich is necessary to give sufficient velocity to obtain satisfactory self clearing action of the cinders. .This construction limits the length of the stack extension that can be used, and determines the height of the exhaust pot that must be used.

The present invention proposes to lengthen the stack 10% to 20% or more, which is a substantial increase over the conventional arrangement. To do this the table plate must be lowered to a position such a height above the bottom of the smokebox that the area under it is reduced, and is less than 50% to 60% of the gas area'through the lines and tubes of the boiler. This produces an added restriction and a definite reduction of flow to the gases such that the steaming qualities and the economic performance of the locomotive are adversely effectedand the capacity at the higher coal rates limited below the maximum possible attainable.

To avoid this added restriction and the reduction of flow to the gases, and at the same time permit the stack to be extended so as to increase the efficiency of the boiler, the capacity of the locomotive and the steaming qualities, I have discovered that the sides of the diaphragm must be cut away in amount equal to the reduced area under the table plate. The cut-outs in the diaphragm must be so located that the netting will not be exposed to direct flow of the gases and cinders, thereby preventing wear or erosion of same.

In substance, the invention contemplates, first lengthening the stack (10% or more over the conventional stack) to obtain increased efficiency and capacity ofthe locomotive, second passing the products of combustion to-the stack through av restricted area under the table plate (less than 60% of the gas area through the tubes and flues of the boiler), and third, forming cutouts in the diaphragm to compensate for the decreased area under the table plate.

The cut-outs in the diaphragm permit the portion of the gases coming from the tubes and flues, above the level of the table plate to pass directly to the stack without having their direction changed instead of passing through a number of right angle turns or a longer and tortuous path under the draft and table plate. before being ejected as in the conventional arrangement. This improvement decreases the resistance to the flow of gases and further increases the capacity of the locomotive and improves the steaming qualities of the boiler.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a front elevation of a locomotive smokebox arrangement constructed in accordance with the invention, with the smokebox door or cover removed.

Figure 2 is a longitudinal sectional view taken on the line 2--2 of Figure 1.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, I!) designates the extension of a boiler shell ahead of the front flue sheet, not shown. A metal diaphragm 1| is secured to the shell through the medium of angle iron brackets l2 and extends from the top of the shell to a point short of the bottom of the shell, as shown in Figure 2. The lower portion of the diaphragm is cut away on both sides to provide openings [3, as shown in Figure 1, through which, and the space underneath the diaphragm, the gases of combustion may be drawn without constriction which would otherwise occur when the remaining parts or members of the smokebox arrangement are constructed and relatively located as will be presently described.

In further carrying out the invention the smoke stack 14 is provided with a depending stack extension I5 which terminates at the bottom in a flared end or bell l6 which is disposed a predetermined distance above the bottom of the diaphragm II. The purpose of this extension is to increase the linear length of the smoke stack. Thus the smoke stack in this embodiment is 10% to 20%, or more, longer than conventional stacks.

An exhaust pipe l1 extends through the bottom of the shell of the smokebox in axial alignment with the smoke stack. The exhaust pipe is equipped with a nozzle [8 having a conventional basket bridge IS. The exhaust pipe is much shorter than is conventional due to the increase made in the linear length of the stack and the lowering of the table plate 20 in carrying out the invention.

The table plate 20 is secured to the top of the exhaust pipe in any preferred manner and extends in a plane below, and spaced forwardly from, the bottom of the diaphragm II. The table plate is provided with an upwardly extending flange or plate 9 at the rear side to break up cinders impinged thereagainst. Walls 2| of netting rise from. the table plate and are connected at the top by a netting wall 22 which is supported upon a flange 23 carried by the bell l6 of the stack. A front wall 24 of netting is inclined downwardly toward the table plate 20 so'that the table plate extends forward a greater distance from the exhaust nozzle toward the front of the smokebox than it does toward the diaphragm. The distance forward from the nozzle is such a distance that .the area immediately ahead of thescreen device, including the sloping front wall thereof, to the front of the smokebox is less than the gas area through the flues and tubes of the boiler, thereby preventing excessive cinder accumulation at the bottom of the smokebox ahead of the table plate and adjacent to the front of the smokebox 25.

As a result of this construction the netting will not be used as a direct impinging surface for cinders coming directly from the fiues or tubes but instead the table plate 20 and diaphragm II will receive the shock of impact and the long life and durability of the netting will thus be promoted.

The stack extension I5, in practice, is arranged in such a manner that the distance between the top of the nozzle l8 and the bottom of the bell i6 is more than 50% of the stack diameter and less than of the stack diameter. By virtue of this arrangement the nozzle produces satisfactory results and will have a negligible efiect on the flow of the gases than when the top of the nozzle is located at any other height between the table plate 20 and bell l 6 of the stack.

The table plate 20 in the present embodiment is disposed at a lower position in the smokebox than ordinarily is the case and this permits of the stack being extended downwardly a greater length than ordinarily to give an appreciable increase in efficiency of the smokebox arrangement. The area under the table plate is less than required to produce a velocity high enough to insure the cinders being carried forward and eventually broken up so that the cinders will pass through the netting and out of the stack into the atmosphere. However a restriction cannot take place under the table plate, for the openings l3, previously described, permit the products of combustion to pass to the smokebox without any reduction in velocity whatsoever in their fiow.

In practice the area under the table plate bears a predetermined ratio to the areas of the openings in the diaphragm, as will be understood from the following. If the gas area through the tubes and fines is 1300 square inches and the minimum area under the draft plate 65% of this area then the area under the draft plate would be 845 square inches, in the conventional smokebox arrangement. When the table plate is lowered, as proposed by this invention, to permit the stack to be lengthened materially, the area under the table plate will of course be considerable less than this amount. If the table plate is located at such a height as to provide an area under the table plate of 50% of the gas area of the fiues and tubes, then the area would be 650 square inches, or a reduction of square inches less than the conventional arrangement.

This reduction in area would increase the restriction to the flow of gases beyond that necessary to give sufficient velocity to the gases to obtain satisfactory self clearing action of the cinders and would reduce adversely the flow of gases. To compensate for this added restriction, the diaphragm is out out on each side in total amount equal to the decreased area under the table plate. The .area of the cut away portion should equal the difference between the minimum area of the conventional construction, and. the minimum area of the construction covered by this invention, or the difference between 845650=195 square inches total. This is divided between each side out out or is 97 /2 square inches per cut out.

If the table plate is lowered to a position which results in the gas area under same being only 40% of the gas area through the tubes and flues, the difference as in the above case would be 325 square inches. The area of the cut away portion on each side of the diaphragm would be one half of this or 162 square inches.

In practice it has been found that when the exhaust nozzle l8 has a parallel bore and of a length not less than of, and not more than twice its diameter, increased efficiency results with the stack positioned with respect to the nozzle as hitherto described.

From the above description it is thought that the construction and operation of the invention will be fully understood without further explanation.

What is claimed is:

l. A locomotive smokebox arrangement comprising a boiler shell forming a smokebox, a diaphragm extending from the top of the shell to a point short of the shell bottom, the lower portion of the diaphragm being cut away adjacent the shell to form openings at both sides of the diaphragm through which products of combustion may be drawn direct to the stack, a smoke stack terminating at the bottom adjacent to the bottom of the diaphragm and above the bottom of the diaphragm, an exhaust steam nozzle in alignment with the stack and terminating at the top below the plane of the bottom of the diaphragm, a screening device housing the bottom of the smoke stack and the top of the nozzle, and an imperforate table plate connected to the top of the exhaust pipe and forming the bottom of the screening device, said table plate being disposed at such a height above the bottom of the shell as to form a restricted area underneath the table plate insufiicient for the effective passing of gases to the stack, said openings in the diaphragm compensating for the restriction and promoting effective passing of gases to the stack.

2. A locomotive smokebox arrangement .comprising a boiler shell forming a smokebox, a diaphragm extending from the top of the shell to a point short of the shell bottom, the lower portion of the diaphragm being cut away adjacent the shell to form openings at both sides of the diaphragm through which products of combustion may be drawn, a smoke stack, the smoke stack terminating at the bottom adjacent to the bottom of the diaphragm and above the bottom of the diaphragm, an exhaust steam nozzle in alignment with the stack and terminating at the top below the plane of the bottom of the diaphragm, a screening device housing the bottom of the smoke stack and the top of the nozzle, and a table plate connected to the top of the nozzle and forming the bottom of the screening device, said table plate being disposed below and spaced from the bottom of the diaphragm, the screen device extending a greater distance from the nozzle toward the front of the smokebox than it does toward the diaphragm, the area ahead of the screen device to the front of the smokebox being less than the gas area through the tubes and fiues of the boiler in order that the velocity of the gases will be sufiicient to prevent excessive accumulation of cinders between the end of the table plate and the front of the smokebox, said table plate being disposed at such a height above the bottom of the shell as to form a restricted area underneath the table plate insufficient for the efiective passing of gases to the stack, said openings in the diaphragm compensating for the restriction and promoting efi'ective passing of gases to the stack.

3. A locomotive smokebox arrangement comprising a boiler 'shell forming a smokebox, a diaphragm extending from the top of the shell to a point short of the bottom of the shell, a smoke stack, the smoke stack terminating at the bottom adjacent to the bottom of the diaphragm an exhaust steam nozzle in alignment with the stack, a screen box housing the bottom of the smoke stack and the top of the nozzle, a table plate forming the bottom of the screen box, the lower portion of the diaphragm being cut away adjacent the shell to form openings at both sides of the screen box through which products of combustion may be drawn into the stack, the table plate being disposed at such a height above the bottom of the shell to form a restricted area underneath the table plate insufiicient for the effective passing of gases to the stack, said restricted area having a predetermined ratio to the gas area through the tubes and flues of the boiler, the area of said openings in the diaphragm bearing a predetermined ratio to said restricted area to compensate for the restriction and promote effective passing of gases to the stack.

WALTER F. COLLINS. 

